Alerting feature for RF availability of mobile subscriber

ABSTRACT

An exemplary method in a wireless telecommunication system determines that a radio frequency (RF) communications link is not available to a wireless mobile. Information about a party originating a call to the wireless mobile is received and stored in a record associated with the wireless mobile. An alert flag associated with the wireless mobile is set. Upon determining that an RF link has become available to the wireless mobile and upon detecting the presence of the set alert flag, a communication action is automatically taken by which the party is made aware that an RF link is available to the wireless mobile, such as by sending a message to the party based on information stored about the party in the record.

BACKGROUND

This invention is generally directed to telecommunications and is morespecifically directed to features related to wireless subscribers andtheir availability.

Modern telecommunication systems provide a variety of features forsubscribers. For example, wireline telephone subscribers may utilizeincoming caller identification, voicemail, speed dialing, conferencingand call waiting to name a few of the available services and features.Some telephone companies also offer wireline subscribers a service inwhich a call will automatically be established between the calling partyand a called party that had a busy line during an initial callorigination when the called party's line becomes not busy. In general,wireline telephone subscribers have available many call services andfeatures that are not available to wireless subscribers. This is due inpart to the substantial history and development of wireline switchingcapabilities as compared to the relatively short history of wirelesscommunication systems. It is also partially due to inherent differencesbetween wireline and wireless systems, i.e. a wireline subscriber's lineis always supported by the same telecommunication switch and is normallyalways connected as compared to a wireless subscriber that may be servedby a variety of telecommunication switches at different times and maynot be connected or available for significant periods of time.

Calls placed to a wireless subscriber have a substantially greaterlikelihood of not being completed as compared to calls placed to awireline subscriber. As used herein “being completed” refers to theability of the telecommunication system to establish a communicationlink to the called party's consumer premises equipment (wireless handsetor wireline telephone) in response to a call origination request. A callorigination to a wireless subscriber may not be completed due to avariety of factors. For example, the wireless subscriber's handset maybe turned OFF or a radio frequency (RF) link between a supporting basestation and the subscriber's handset may not be available. Even while inareas of generally good RF signal strength, a wireless subscriber mayenter a localized area in which RF communications are poor or notavailable. Commonly known “RF dead zones” include tunnels, undergroundparking garages, areas within buildings surrounded by material thatprovides RF shielding or substantial attenuation, etc.

What happens when a party originates a call to a wireless subscriberthat does not complete? The calling party will be typically given noindication of the reason for the lack of completion. Even for thosewireless systems which provide an announcement indicating that thecalled wireless subscriber cannot be reached or located, the callingparty is left to wonder whether the wireless subscriber is not active(e.g. cellular telephone turned OFF) or whether the wireless subscriberis merely experiencing temporary RF link unavailability, e.g. being inan RF dead zone. Other than an option of leaving traditional voicemailfor the unavailable wireless subscriber, the calling party is left toperiodically initiate new call originations to the desired wirelesssubscriber in an attempt to establish communications. Thus, there existsa need for improved services related to calls desired to be establishedwith wireless subscribers.

SUMMARY

It is an object of the invention to provide a solution to this need.

An exemplary method in a wireless telecommunication system determinesthat a radio frequency (RF) communications link is not available to awireless mobile. Information about a party originating a call to thewireless mobile is received and stored in a record associated with thewireless mobile. An alert flag associated with the wireless mobile isset. Upon determining that an RF link has become available to thewireless mobile and upon detecting the presence of the set alert flag, acommunication action is automatically taken by which the party is madeaware that an RF link is available to the wireless mobile, such as bysending a message to the party based on information stored about theparty in the record.

The invention in one implementation encompasses an apparatus such as amobile switching center that is instrumental in implementing the method.

DESCRIPTION OF THE DRAWINGS

Features of exemplary implementations of the invention will becomeapparent from the description, the claims, and the accompanying drawingsin which:

FIG. 1 is a block diagram of an exemplary telecommunication systemsuited for incorporating an embodiment of the present invention.

FIG. 2 is a flow diagram of exemplary steps in accordance with anembodiment of the present invention.

DETAILED DESCRIPTION

FIG. 1 is a block diagram of a telecommunication system 10 suited forincorporation of an embodiment of the present invention. A mobileswitching center 12 supports the routing of calls and traffic such astext messaging to and from wireless communication devices. An exemplaryRF communication link is supported by base station 14, tower 16 andcellular antenna 18. It will be understood that a typical system willutilize a plurality of such RF communication links that can all besupported by mobile switching center 12 wherein each RF communicationlink may comprise a cellular service area. Exemplary wireless devices20, 22 and 24 are within the area of service, i.e. anticipated RFcoverage area, normally provided by antenna 18. The wireless devices arealso referred to herein as mobile devices or just mobiles.

A home location register (HLR) database 26 stores records correspondingto mobiles for which database 26 is the home register. As is known, HLRdatabase 26 provides initial log-on registration, authentication andbilling support. The HLR database 26 is connected to the mobileswitching center 12 and an adjunct service node 28 that is capable ofproviding additional processing and services with respect to thehandling and routing of wireless calls and traffic. The public switchedtelephone network (PSTN) 30 is coupled to the mobile switching center 12and supports a plurality of wire line telephones of which telephone 32is one. In this example telephone 32 is an ISDN telephone capable ofvoice and data (text) communications.

Within the area of coverage provided by cellular antenna 18 is arecreational walking path 34 that passes through a tunnel 36. The tunnelis oriented and constructed such that it creates an RF dead zone formobiles in the tunnel with regard to RF communications from any cellularantenna. Thus, as shown the subscriber utilizing mobile 20 is insidetunnel 36 and hence RF communications will not be possible until thesubscriber exits the tunnel.

In accordance with an embodiment of the present invention, an alertingfeature is made available to telephone subscribers wherein an alert isprovided to the party originating a call to a mobile that does not havean RF communication link when an RF communication link with the callmobile becomes available. As an example, assume that a calling partyassociated with telephone 32 or mobile 24 originates a call to the userof mobile 20 while the called party is within tunnel 36. The call willnot complete since an RF communication channel with mobile 20 is notavailable. If the calling party subscribes to the alerting feature or ifthe communication provider makes the alerting feature available to allsubscribers, the calling party will at least be automatically notifiedwhen an RF communication link with mobile 20 becomes available. As willbe discussed in more detail with regard to FIG. 2, the notification mayconsist of a predetermined text message originated by the infrastructureequipment and sent to the calling party such as by a short messagingsystem (SMS) message. Alternatively, the infrastructure equipment couldautomatically take other actions such as establishing the call by makinga call origination to the called party and calling party andconferencing the calls, assuming both corresponding telephones areactive and not busy.

FIG. 2 is a flow diagram of steps of an illustrative method inaccordance with the present invention. In step 100 a call origination ismade to a mobile. For example, the mobile switching center 12 willrecognize that an incoming call request is to one of its served mobiles.In step 102 a determination is made of whether the called mobile (CM) isin a dead RF zone. The mobile switching center 12 determines that thecalled mobile is not currently registered and/or active based on aninquiry to HLR database 26. Since an RF channel is not available to thecalled mobile, the mobile may be deemed to be in a dead RF zone. Ofcourse, it may be that the user of the called mobile may have merelyturned the mobile OFF. A NO determination by step 102 means that an RFchannel is available to the called mobile and hence the call request isprocessed normally as indicated at step 104.

A YES determination by step 102 results in processing by step 106 inwhich it is determined if the calling party (CP) is a subscriber of theRF alert feature. This determination may be carried out by mobileswitching center 12. A NO determination by step 106 results in the callrequest being routed to the system's Not Available (NA) process such asa voice mailbox corresponding to the called mobile. A YES determinationby step 106 causes information about the CP to be logged in a recordassociated with CM including the setting of an RF alert flag. The recordmay be stored in the HLR database 26 associated with information storedfor the corresponding called mobile. The stored information about the CPincludes at least sufficient information to permit a message to be sentto and/or call to be placed to the CP. For example, this could consistof an e-mail address, packet location identification and/or telephonenumber associated with the calling party.

In step 112 a determination is made of whether an RF link to the calledmobile is now available. The mobile switching center 12 in cooperationwith the HLR database 26 can make this determination. A NO determinationreturns processing to the beginning of this step effectively creating await state. A YES determination means that an RF channel is nowavailable to the called mobile and causes processing to continue to step114 in which a determination is made of whether an RF alert flag is setfor the called mobile. The mobile switching center 12 can determine ifan alert flag associated with the previously called mobile, which hasjust become registered and active, has been set. A NO determination bystep 114 results in the normal availability processing of the now activemobile as indicated in step 116. That is, the previously called mobilecan receive and originate calls and traffic. However, the lack of an RFalert flag being set for the corresponding activated mobile will notcause any alerts to be originated even if an unsuccessful prior callattempt had been made. A YES determination by step 114 results in thereading of the previously stored information about the calling party.Additionally, action is initiated automatically involving at least someform of communication to the party that previously called. This actionmay be accomplished by the mobile switching center 12 in combinationwith the HLR database 26. The action to be taken can be determined bythe telecommunication provider. The action may consist of the generationand transmission of an SMS message to the party that previously calledinforming the party that the previously called mobile is now available.Alternatively, the mobile switching center could be programmed tooriginate calls to both the previously called mobile and the callingparty, with these calls being conferenced, to effect the automaticgeneration of a delayed call origination between the parties.

As an alternative to the mobile switching center 12 conducting much ofthe processing for the subject alerting feature as explained above, theadjunct service node 28 in conjunction with the mobile switching center12 and HLR database 26 could be utilized as the primary processresponsible for effectuating the alert feature. In a furtherimplementation, the origination switch that serves the initial callingparty could be utilized to generate the alert or signal to betransmitted to the calling party upon the called mobile becomingavailable. In the latter implementation SS7 or other intranetworksignaling could be utilized to convey the information to the originatingswitch from the mobile switching center 12 and HLR database 26.

In another embodiment it is possible to make a determination withimproved accuracy that the called mobile is in an RF dead zone asopposed to the called mobile merely being turned OFF. For example, if atime stamp kept in the HLR database 26 relating to a mobile shows thatthe subject mobile had been recently registered and active, e.g. withinthe few minutes or other predetermined interval of time, but is nowinactive/unavailable, an assumption that the mobile entered a dead RFzone is more likely. That it is, if the subject mobile has not beenregistered/active for a longer period of time, e.g. 20 minutes or anappropriate time interval, it is more likely that the mobile is eitherturned OFF or out of the accessible communication region. Thisinformation could be utilized in making the decision of the step 102 inorder to provide a higher probability that the called mobile is onlytemporarily unavailable due to being in an RF dead zone. This can beused to inhibit the alerting feature if it is desired to only permitalerts while the mobile is temporarily unavailable. Alternatively, thecalling party could be given the option of activating the alert featurefor only situations, i.e. as determined by the time the mobile has beenunavailable, where the mobile is likely in an RF dead zone.

In a further implementation the calling party may be offered an electionas to the type of action to be taken upon the called mobile becomingavailable. For example, a message transmitted by the mobile switchingcenter 12 (or adjunct service node 28) to the calling party may adviseof the possible options such as sending an alert message to the callingparty upon the mobile becoming available or automatically initiating acall between the parties upon the mobile becoming available. The callingparty may exercise the selected option by sending a return message or byentering a DTMF signal corresponding to a particular option.

A situation may exist in which a party may know that a mobile iscurrently unavailable. For example, the party desiring to communicatewith the mobile may know that the mobile user is a passenger on acommercial flight in which cellular communications are not permitted.Even so, the party desires to communicate with the mobile user as soonas the flight is over and the mobile is activated. Assuming that theparty desiring early communications with the mobile is a subscriber tothe RF alerting service, the party could send an additional signal, e.g.a suffix #2, following the entry of the normal telephone number of themobile as an instruction to the infrastructure equipment to set acorresponding alert flag for the mobile. This would be advantageous inthat resources are conserved since the cellular infrastructure equipmentcould merely initiate the alert feature directly without having to firstattempt a call origination to a mobile which is known not be toavailable. In such a situation the mobile switching center 12 wouldrecognize the signaling suffix and directly initiate implementation ofthe RF alert feature in cooperation with the HLR database 26.

The steps or operations described herein are just exemplary. There maybe many variations to these steps or operation without departing fromthe spirit of the invention. For instance, the steps may be performed ina differing order, or steps may be added, deleted, or modified.

Although exemplary implementations of the invention have been depictedand described in detail herein, it will be apparent to those skilled inthe relevant art that various modifications, additions, substitutions,and the like can be made without departing from the spirit of theinvention and these are therefore considered to be within the scope ofthe invention as defined in the following claims.

1. A method implemented by a wireless telecommunication systemcomprising the steps of: receiving a call origination request from aparty for a call to be placed to a wireless mobile; determining if thecall origination request includes a special signal entered by the party,where the special signal is not part of the telephone number of thewireless mobile; upon determining that the special signal is present:storing information about the party where the information is stored in arecord associated with the wireless mobile; setting an alert flagassociated with the wireless mobile; determining that an RF link hasbecome available to the wireless mobile; detecting the presence of thealert flag for the wireless mobile in response to the determination thatthe RF link has become available to the wireless mobile; in response tothe detection of the alert flag, automatically taking a communicationaction by which the party is made aware that an RF link is available tothe wireless mobile.
 2. The method of claim 1 wherein the communicationaction comprises sending a text based message to the party where themessage is indicative of an RF link is available to the wireless mobile,an address of the party used for sending the message being stored andretrieved from the record.
 3. The method of claim 1 wherein thecommunication action comprises automatically initiating a call betweenthe party and the wireless mobile, a telephone number of the party beingstored and retrieved from the record in order to initiate the call. 4.The method of claim 1 further comprising the step of determining whetherthe party subscribes to an alerting feature, only if the partysubscribes will the communication action be taken.
 5. The method ofclaim 1 wherein the step of storing information about the partyoriginating a call to the wireless mobile comprises storing theinformation in a record in a home location register by which thewireless mobile is authenticated as a valid user in the wirelesstelecommunication system.